The present disclosure relates to foundry-agnostic post-processing methods for wafers and, more particularly, to foundry-agnostic post-processing methods for wafers where alternative material substrates are bonded to wafers to create customized devices with improved performance.
In electronics, a wafer is a thin slice of semiconductor material that is used for the fabrication of integrated circuits and in photovoltaics. The wafer serves as the substrate for microelectronic devices built in and over the wafer and undergoes many microfabrication process steps such as doping or ion implantation, etching, deposition of various materials and photolithographic patterning. At a final stage, individual microcircuits formed on the wafer may be separated from one another by a dicing process and packaged for shipping.
Wafers are frequently formed of silicon (Si) or silicon germanium (SiGe) and may include low resistivity (LRS) substrates, high resistivity (HRS) substrates and silicon-on-insulator (SOI) substrates with a buried oxide (BOX) layer disposed on an HRS substrate. Over time, it has been demonstrated that the higher resistivity substrates can in some cases improve certain aspects of device performance by reducing parasitic substrate losses, such as collector-substrate capacitance. However, foundries where wafers are typically processed do not have the capacity for providing wafers with substrates that are more resistive than the LRS, HRS and SOI substrates.